Watch crystal grinding apparatus



March 9, 1954 L. SHARP ETAL 2,671,295

'wmrcu CRYSTAL GRINDING APPARATUS Filed bot. so, 1950 v a Sheets-Sheet 1 INVENTOR. GRADY L. SHARP J WILLIAM A. .SHAR-P March 1954 e. L. SHARP ETAL 2,671, 9

WATCH CRYSTAL GRINDING APPARATUS Filed Oct. 30, 1950 3 Sheets-Sheet 2.

NVENTOR. GRAD) L. HARP WILL/AM A-SHARP March 9, 1954 G. L. SHARP ET AL 2,671,295

WATCH CRYSTAL GRINDING APPARATUS Filed Oct. 50 1950 3 Sheets-Sheet s INVENTO GRAD) 1.. SHARP WILL/AM ASHARP Patented Mar. 9, 1954 WATCH CRYSTAL GRINDING APPARATUS Grady L. Sharp and William A. Sharp, Albuquerque, N. Mex.

Application October .30, 1950, Serial No. 192,925

The present invention relates to machines for automatically grinding watch crystals or other types of crystals to any desired shape or size, and, if desired, with bevelled edges at any desired angle of bevel. The machine is arranged to operate entirely automatically so that once a blanl; crystal has been set on the machine and it has been set in operation, the machine will thereafter automatically operate to grind the crystal to the dc eired shape and size to fit a particular bezel. The machine operates entirely automatically without attention from the operator, and, if desired, it may be automaticall stopped by a timer after .a predetermined period of time. One of the objects of the invention is to provide a machine fully automatic as in the foregoing, which will grind a crystal to a desired shape andsize without the attention of the operator.

Another object of the invention is to provide an automatic crystal grinding machine having means wherein a crystal-holding mechanism is provided and which is operated by a mechanism arranged to rotate the crystal and to Cause it to move in a manner so .as to exactly follow the shap of a watch bezel which is rotated by other means.

Another object of the invention is to provide a crystal grinding mechanism having means for rotating a watch bezel and having follower means associated with the bezel and cooperating means whereby a crystal to be ground can be caused to follow the exact shape of the watch bezel where y to grind the crystal in a manner to exactly fit the watch bezel.

Another object of the invention is to provide an arrangement as in the foregoing object, wherein the rotation of the crystal and the bezel are exactly synchronized to produce a ground crystal to fit the bezel exactly,

Another object of the invention is to provide an arrangement as in the foregoing objects including automatic means for moving, the crystal mounting or carrier means transversely so as not to cause a groove to be worn in the grinding wheel.

Another object of the invention is to provide an automatic crystal grinding mechanism, inclucling a mounting fram for the crystal, the frame having a tilt adjustment whereby a bevel can be ground .on a watch crystal at any desired angle.

Another object of the invention is (to provide a .m ysta l grinding mechanism, comprising a means whereby a watch bezel may be rotated, a tollower associated with the bezel, means whereby the Claims. (01. 51. o 1) crystal is caused to m re in exa t i rmity w said IfO l QL. the arran eme t involving a frame for mounting the cry t l, and a djustm n whereby its position may be adjusted toward. and away from the grinding wheel to accommodate the mechanism to crystals or a s of greater size than the to Whil h the crystal is to be ground.

Another object of t e invent o o p ovide in a crystal rindin machine a moun ng Home and holder for crystals compri g two spindles having means to synch on ze tho speed an mbearing resilient rods f r clamping the crystal. the arrangem nt compr s ng a ma uall re iprocatable stem and spr n ie sioncd la s h h may he moves in o a p siti n y he s em to clamp the crystal.

Another object of the invention is to provide an mp oved c uck for use in a c y ta g nd n machine wherein two pairs .of diametrically opposed tows are provid d, ea h pair of Jews eing perated by a s rew threaded stem hav g i i and r ght h nd rea s whereby the two pa s of i-aws may b caused to en a e the i side o a Watch bezel whereby to firmly hold the bezel whereby it may be rotated and it may have a Iollower c used to accurately .Iollow the inside contour of the bezel as it is rotated.

Further objects and numerous advant g o our invention will become apparent from the jollowing detailed specifications and annexed drawings wherein Fig. 1 is a general perspective View of e watch crystal grind g mechan sm of our invention.

Fig. 2 is an enla ged detailed view f t e rame. mounting and holding mechanism 101 the crystal to be ground.

Fi 3 is a de ailed view of the universal join drive for the arbors which rotate the crystal.

Fig. ,4 is a detailed view of a modifiediorm of flexible coupling to the cryst l d i e Fig. 5 is a detailed view of the improved rotatabl chuck m chanism ior mounting androtatin the watch bezel.

Fig. 6 is another view of the mechanism .of Fig.5.

Fig. 7 is a detail view of a part .ofLFig. ,1

Referring now more in detail to Fig, 1 of the drawings the entire mechanism may be mo nte ona rectangular base m. Numeral .12 desi nate an electric motor of su t ble size and speed ,ior driving themcohanism- .On the shaft of the motor 112 is a grinding wheel 14 .of conventional type whi h i a ache to the motor shaft by a ut as shown. on th 3 end of the shaft of motor I2 is a pinion gear I6 which meshes with a large gear I8 on a shaft 28. The shaft 28 is mounted in upright pedestals from the base I8, having bearings 24 and 28 as shown. On the end of the shaft 28 is a bevel gear 38 which meshes with another bevel gear 32 on a rightangled shaft 84 which is mounted in a pedestal bearing 38, Also on the shaft 34 is another bevel gear 38 which meshes with the bevel gear 48 on a right-angle shaft 83 which will be referred to again presently. The shaft 34 also carries and drives the improved rotatable chuck of our invention which will be referred to again presently.

The gear ratios of gears I8 and I8 may preferably be such that the shaft 28 rotates at a speed of 6 revolutions per minute. The gear ratios of the gears 38 and 32 may preferably be such that the shaft 34 rotates at a speed of 8 revolutions per m nute, so that the chuck 42 rotates at '3 revolutions per minute. As will presently be described the crystal itself is rotated at exactly the same synchronized speed as the chuck 42, that is, a speed of 3 revolutions per minute. The manner of drive of the crystal will be described presently.

The chuck 42 has 2 pairs of diametrically opposed jaws as can be seen in Fig. 1. These jaws protrude from the interior of the chuck 42 and each pair is individually adjustable by knurled knobs 44 and 46. The details of the improved chuck 42 will be described presently in connection with Figs. and 6. The 2 pairs of jaws of the chuck 42 engage internally within a bezel 48 which is shown as rectangular in Fig. l and the outer surface of these jaws are knurled or roughened so as to engage the interior of the bezel without slipping. Numeral 52 designates a curved, pointed member which engages within the interior of the bezel 48 in the groove in the bezel in the manner of a cam follower and exactly follows the interior contour of bezel 48 as it rotates. The member 52 is a part of a mechanism which it operates to cause the movement of the crystal to be ground to exactly follow the movement of the bezel 48 and this mechanism will be described presently.

Referring now to the rotatable drive for the crystal mounting, the manner of this drive will be described. The details of the rotary drive for the crystal mounting are shown more clearly in Fig. 3. Referring now to Fig. 3 of the drawings numeral I28 designates a pedestal bearing in which is mounted shaft 93 of bevel gear 48. Bevel gear 48 through its shaft drives the shaft 86 through the universal joint 94 which serves the conventional purpose of universal joints. The shaft 96 is square for part of its length, as shown, and it engages in a square bore or opening in a shaft 98 to provide slidable adjustment as between these two shafts, that is, the arrangement provides an extensible coupling. At the other end of the shaft portion 98 is another universal joint 92 which connects this shaft to a shaft mounted in a transverse member I88 which attaches to the frame of the crystal mounting as will be described presently. On the end of this shaft is another bevel gear 98 which meshes with a rightangle gear 88 on the end of the shaft H4, which, as may be seen in Fig. 1 forms one of the spindles which drive the crystal as will be described. From the foregoing it can be seen that the bevel gear 88 drives one spindle of the crystal rotating mechanism. It will also be observed that the entire gear train comprising gears 98, 88 and the gear 82 on the same shaft as gear 88 may be moved transversely along with the crystal mounting frame, as will be described shortly. M0vement of this gear train both transversely and toward and away from the grinding wheel I4 is permitted by the universal joints and the sliding coupling formed by the shafts 96 and 88. The mechanism for moving the mounting frame of the crystal will next be described.

Referring now again to the pointer 52 which engages within the bezel 48, this member is mounted on a swivel 53 as shown, which is carried by a slider member 56 which is slidable toward and away from the grinding wheel in a channeled base or frame 54. The slider member 56 has a vertical upright 58 and the slider is normally urged away from the grinding wheel, by a tension spring 58, as shown. Thus it can be seen that the mounting of the pointer or follower 52 is such that it can accurately follow the contour of any bezel no matter what its shape, whether curved or otherwise.

The mechanism providing for transverse movement of the mounting frame for the crystal comprises a transverse channel member 82, as shown mounted on the base I8. Slidable within this channel member 62 is a slider 84 which can slide transversely, as shown. The slider 64 is pivoted by pin I86 to an arm as shown on the end of which is a circular member 22 which engages 7 around an eccentric disc 28 on the shaft 28. Thus it can be seen that as the shaft 28 rotates, the action of the eccentric 28 within the ring 22 is to cause the slide 84 to slide back and forth in the slider base member 82.

Upstanding from the slider 84 are upright members I82 and I04 and engaged between these members on shaft 66 is cylindrical member 78 and from this member extends upwardly a shaft 12. The shaft I2 is rotatable in the cylindrical member 18 in the manner of a swivel for a purpose which will presently be made clear. On the end of the shaft or stem I2 is a U-shaped frame I3, as shown, which inclines towards the grinding wheel I4 in the position shown in Fig. 1.

Spaced inwardly from the outer ends of the legs of the U-shaped member 73 and journaled for rotation therein is a shaft 14 and fixedly secured to the outer ends of the said shaft 74 are gears 16 and 88. Adjacent the ends of the legs of the U-shaped member I3 are a pair of axially aligned holes and in these holes are journaled for rotation the separate axially aligned shafts H4 and HE. A gear 82 is fixed to the shaft II4 immediately adjacent the outer face of a leg of the member 33 and meshes with the gear 88 and a bevel ear 88 is fixed to the end of said shaft I I4 to mesh with the drive gear 98 previously described. A gear 18 associated with the shaft H8 meshes with the gear IS. The shafts H4 and H6 cooperate to drive the watch crystal as will be presently described in greater detail. The gears 88 and 82 and I6 and I3 are sized so that the shafts I I4 and II8 will be positively driven at exactly the same speed. On the end of the shaft I I 8 is a knurled knob 86 for manually producing the clamping and unclamping operation of the crystal as will be described presently. From the foregoing, it can be seen that through the shaft 28 and the eccentric 28 the frame which mounts the crystal is moved transversely as respects the grinding wheel 48 and this is a uniform back and forth motion as can be seen, to prevent a groove being worn in the grinding wheel I4 by the crystal.

The details of the manner of clamping the crystal to "be ground. between the others will he described presently in connection with 2.

The mechanism as previously described for prodncing motion of the crystal in conformity with the bezel includes in addition to the upright 58 extending upwardly from the slider '56, an arm 50 attached by slot and a pin, as shown, to the upper end of upright 58 and the opposite end of this am engaging the shaft or spindle H4. As may be seen in Fig. "7, coil spring 53 attached to arm on and upright 58 normally urges arm so in a direction to bring the pin in upright 58 toward the end of slot 6!. Thus from the foregoing it can be seen that as the pointer or follower 52 tollows the interior contour of bezel t8, the slider 53 is similarly moved through the arm 59, the frame on which the crystal to mounted is rnoved to- Ward and away from the grinding wheel in exactly the same manner. At the same time, the crystal is being rotated at exactly the same speed as the bezel '38. As previously pointed out, these various movements of the crystal are permitted by the universal joints and coupling in the drive to the crystal. The non rigid attachmentof arm 6U to upright 58 provides self-adjustment of the parts to accommodate crystals or blanks larger than the bezel to which they are to be ground to fit.

Referring now to Fig. 2 of the drawings, the I 'rnounting of the frame which holds the crystal is shown detail in this figure. As may he seen in the figure, the slider -6 is shown, which slides in the block 62 mounted on base to as previously described. The stem 72 which carries the frame which mounts the crystal, as shown, extends into the cylindrical member "Hi and is firmly held there by the set screw 68. The cylindrical member Til is "pivotally mounted on a shaft or spindle $6, the ends of which engage in bearings in the uprights H12 and Hi l as shown. Thus as can be seen from Fig. 2 the frame can be pivoted about the'shaft or spindleGG in a direction into or away from the grinding wheel, the spindle 66 beingheld in place byset screw I38.

Similarly, by loosening the set screw 68 the frame mounting the crystal can be rotated about the axis of stem 52 for the purpose of grinding a bevel on the edge or the crystal, as will bereferred to again presently. As maybeseen in Fig. "2 the gears 80 and T6 on the ends ofshatt'l'a mesh with the gears '82 and 18 in the manner previously described. As shown in Fig. 2 on the ends of the .arbors I M and H6 are resilient cushions or pads 12!] and I22 between which the crystal 84 is firmly engaged. As has already been'pointed out the two arbors are separate, but synchronized and driven at exactly the same speed. Surrounding the arbor H6 and i'ournaled for rotation in the leg of the U-shaped member 73 is a sleeve H8, said sleeve having the gear T8 fixedly attached thereto and being driven thereby. A pin H9 passes loosely through an elongated slot 1 I8 in said sleeve and is fixedly secured in the spindle "I IB. Fixe'dly attached to the sleeve "I i 8 is a transverse member I2 I, as shown, having inwardly ex tending arms 12% and 121 whichare parallel to the sleeve 1 l8. Pivotally attached "to these arms WW and iii "are the jaws "HI! and H2, respectively. Between the transverse "member 12! and the pin H9 is placed a stifi coil spring 123. This spring "normally urges the pin l ['9 inwardly and consequently'the'shaft l ifiwill'b'e braced inwardly andthe jaw 122 will maintain a pressure against the crystal and "the fixed jaw 120. The pin I I9 serves to transmit the sleeve torque to the arbor I1 6. The raw members H0 and 112 are normally urged toward the transverse member by coil springs I24 and I26, as shown. The inner ends of the jaw members are adjacent the sleeve 8 and are engageable with the transverse pin 9 extending through sleeve H8, when the pin I I9 is drawn outwardly by drawing outwardly on the arbor H6 and knurled knob 8%. When the transverse pin I19 engages the inner ends oi jaws H0 and 112 they are rotated about their pivots stretching springs I24 and I26 and the ends of the jaws then engage the edges of the crystal firmly and clamp it. In this operation the coil springs, as can readily be seen, pass over dead center and after passing over dead center hold the jaws firmly against the edges of the crystal 184, thus centering the crystal in and between the clamping jaws 120 and 122.

Referring now more particularly to Figs. 5 and .6 of the drawings the improved rotating chuck 42 is shown detail. The chuck comprises a cylindrical member as shown which is driven by the shaft 36. Each of the individual jaw members operates in a transverse groove as shown in the outer face of the cylindrical member, as shown. At the inner end of each of the jaw members as shown at Mb, 45b, 46b and 41b is a rec tangular block which travels in a transverse groove within the chuck 4-2. [The individual jaws of the two pairs or jaws, are spaced degrees apart as may be seen in Fig. 6 and the transverse grooves in which the individual 'hlock members slide are spaced 90 degrees as shown the figure. Each of the blocks has a screw-threaded bore and passing through the bores are screw-threaded stems 4'9 and 5| as shown, and at the outer ends of the stems are knurled, rotating knobs 46 and 41 for one pair of jaws and 44 and do for the other pair of jaws. Each of the screw-threaded stems extends through the blocks at the ends of one pair of jaws and each-of the stems has righthanded threads on one side and left-handed threads on the other. Thus, it can be seen, that by rotating one of the knobs at either end of one of the screw-threaded stems, its respective pair of jaws may be caused to close together or move apart. in this manner the two pairs of jaws can he made to firmly and accurately engage within a rectangular bezel as shown at In: in Fig. 1, no matter what the shape of the bezel is. As previously pointed out, the outer surfaces of the jaws may preferalolyhe serrated or knurled in order to prevent slipping in their engagement with the 'interiorof the bezel.

The foregoing is representative of preferred forms of our invention. Those skilled in the art will observe that we have provided a very efiective and fully automatic device for grinding watch crystals or other crystals to any desired shape, and to a shape exactly in conformity with the "-bezel to which the crystal is 'to be fitted. It is to be observed that all of the motions and-adjustments of -the mechanism are positive in action and that chose. crystal has been set on the machine for grinding to the desired size, the machine is fully automatic to grind it to the exact size to fit the bez'el without attention from an operator. The machine'may be set in motion and automatically stopped "by a timer, if desired. The mechanism provides convenient mechanical arrangements whereby the frame for mounting the crystal is readily adjustable away from the grinding wheel adapting it for grinding any size crystal -'or blank, even though it is larger than the bezel to-be fitted, and it will au'tomati cally adapt itself, once it has been set, to any size crystal.

By loosening set screw 68 stem 12 may be angularly rotated in hub 10, thus tilting frame 13 so that the crystal is positional at an angle to the grinding wheel for grinding a bevel at any desired angle on the crystal. 9 The arrangement which we have provided for mounting and rotating the bezel is very effective and convenient in that the two pairs of jaws are conveniently adjustable manually, and hold and retain the bezel in a manner such that it cannot get out of adjustment.

The foregoing is representative of a preferred form of our invention and such variations, modifications and alterations as may be made by those skilled in the art are intended to come within the spirit and scope of the claims appended hereto.

We claim: I

1. In a watch crystal grinding machine, a base, a motor having a shaft extending transversely of the base, a grinding Wheel fixed on said shaft, a worm fixed on said shaft, a second shaft extending longitudinally of the base, a worm wheel fixed on one end of the second shaft and meshing with said worm, a third shaft supported transversely of the base, bevel gears connecting the last mentioned shaft and the second shaft, a rocking frame supported from said base adja cent the grinding wheel, crystal holding means carried by the free end of said frame and including alined spindles, a telescopic shaft extending longitudinally of the base, a pair of bevel gears connecting the last mentioned transverse shaft and the telescopic shaft, said gears having a drive speed ratio of one to one, a pair of bevel gears connecting one of the spindles and the telescopic shaft, said last mentioned gears also having a drive speed ratio of one to one, a chuck for engaging a watch bezel fixed on the third shaft, a slide mounted on said base for movement longitudinally thereof, a feeler fixed on the slide for engaging a bezel held in the chuck, an arm projecting upwardly from said slide, and a link connecting the free end of said frame with 3 said arm.

2. In a, watch crystal grinding machine, a base, a motor having a shaft extending transversely of the base, a grinding wheel fixed on said shaft, a worm fixed on said shaft, a second shaft extending longitudinally of the base, a worm wheel fixed on one end of the second shaft and mesh ing with said worm, a third shaft supported transversely of the base, bevel gears connecting the last mentioned shaft and the second shaft, a rocking frame supported from said base adjacent the grinding wheel, the support for said frame including a slide movable transversely of the base, an eccentric disk fixed on the second shaft, an eccentric strap surrounding said disk and having an arm attached to said slide, crystal holding means carried by the free end of said frame and including alined spindles, a telescopic shaft extending longitudinally of the base, a pair of bevel gears connecting the last mentioned transverse shaft and the telescopic shaft, said gears having a drive speed ratio of one to one, a pair of bevel gears connecting one of the spindles and the telescopic shaft, said last mentioned gears also having a drive speed ratio of one to one, means to rock said frame, a chuck for engaging a Watch bezel fixed on the third shaft, a slide mounted on said base for movement longitudinally thereof, a feeler fixed on the slide for engaging a bezel held in the chuck, an

arm projecting upwardly from said slide, and a link connecting the free end of said frame with said arm.

3. In a watch crystal grinding machine, a base, a motor having a shaft extending transversely of the base, a grinding wheel fixed on said shaft, a worm fixed on said shaft, 2. second shaft extending longitudinally of the base, a worm wheel fixed on one end of the second shaft and meshing with said worm. a third shaft supported transversely of the base, bevel gears connecting the last mentioned shaft and the second shaft, a rocking frame supported from said base adjacent the grinding wheel, crystal holding means carried by the free end of said frame and including alined spindles, a telescopic shaft extending longitudinally of the base, a pair of bevel gears connecting the last mentioned transverse shaft and the telescopic shaft, said gears having a drive speed ratio of one to one, a pair of bevel gears connecting one of the spindles and the telescopic shaft, said last mentioned gears also having a drive speed ratio of one to one, means to rock said frame, and means on one of said spindles for gripping opposite edge portions of a crystal to center said crystal.

4. In a watch crystal grinding machine, a base, a motor having a shaft extending transversely of the base, a grinding wheel fixed on said shaft, a worm fixed on said shaft, a second shaft exending longitudinally of the base, a worm wheel fixed on one end of the second shaft and meshing with said worm, a third shaft supported transversely of the base, bevel gears connecting the last mentioned shaft and the second shaft, a rocking frame supported from said base adjacent the grinding wheel, crystal holding means carried by the free end of said frame and including alined spindles, a telescopic shaft extending longitudinally of the base, a pair of bevel gears connecting the last mentioned transverse shaft and the telescopic shaft, said gears having a drive speed ratio of one to one, a pair of bevel gears connecting one of the spindles and the telescopic shaft, said last mentioned gears also having a drive speed ratio of one to one, a chuck for engaging a watch bezel fixed on the third shaft, a slide mounted on said base for movement longitudinally thereof, a feeler fixed on the slide for engaging a bezel held in the chuck, an arm projecting upwardly from said slide, a link connecting the free end of said frame with said arm, and means on one of said spindles for gripping opposite edge portions of a crystal to center said crystal.

5. In a watch crystal grinding machine, a base, a motor having a shaft extending transversely of the base, a grinding wheel fixed on said shaft, a worm fixed on said shaft, a second shaft extending longitudinally of the base, a worm wheel fixed on one end of the second shaft and meshing with said worm, a third shaft supported transversely of the base, bevel gears connecting the last mentioned shaft and the second shaft, a rocking frame supported from said base adjacent the grinding wheel, the support for said frame including a slide movable transversely of the base, an eccentric disk fixed on the second shaft, an eccentric strap surrounding said disk and having an arm attached to said slide, crystal holding means carried by the free end of said frame and including alined spindles, a telescopic shaft extending longitudinally of the base, a pair of bevel gears connecting the last mentioned transverse shaft and the telescopic 9 shaft, said gears having a drive speed ratio of one to one, a pair of bevel gears connecting one of the spindles and the telescopic shaft, said last mentioned gears also having a drive speed ratio of one to one, means to rock said frame, a chuck for engaging a watch bezel fixed on the third shaft, a slide mounted on said base for movement longitudinally thereof, a ieeler fixed on the slide for engaging a bezel held in the chuck, an arm projecting upwardly from said slide, a link connecting the free end of said frame with said arm, and means on one of said spindles for gripping opposite edge portions of a crystal to center said crystal.

GRADY L. SHARP.

WILLIAM A. SHARP.

References Cited in the file of this patent UNITED STATES PATENTS Number Rybicky July 1, 1941 

